Selection and Receipt of Kidney Replacement in Critically Ill Older Patients with AKI.

Background And Objectives: Older patients in the intensive care unit are at greater risk of AKI; however, use of kidney replacement therapy in this population is poorly characterized. We describe the triggers and outcomes associated with kidney replacement therapy in older patients with AKI in the intensive care unit.

Design, Setting, Participants, & Measurements: Our study was a prospective cohort study in 16 Canadian hospitals from September 2013 to November 2015. Patients were ≥65 years old, were critically ill, and had severe AKI; exclusion criteria were urgent kidney replacement therapy for a toxin and ESKD. We recorded triggers for kidney replacement therapy (primary exposure), reasons for not receiving kidney replacement therapy, 90-day mortality (primary outcome), and kidney recovery.

Results: Of 499 patients, mean (SD) age was 75 (7) years old, Charlson comorbidity score was 3.0 (2.3), and median (interquartile range) Clinical Frailty Scale score was 4 (3-5). Most were receiving mechanical ventilation (64%; =319) and vasoactive support (63%; =314). Clinicians were willing to offer kidney replacement therapy to 361 (72%) patients, and 229 (46%) received kidney replacement therapy. Main triggers for kidney replacement therapy were oligoanuria, fluid overload, and acidemia, whereas main reasons for not receiving therapy were anticipated recovery (67%; =181) and therapy not consistent with patient preferences for care (24%; =66). Ninety-day mortality was similar in patients who did and did not receive kidney replacement therapy (50% versus 51%; adjusted hazard ratio, 0.78; 95% confidence interval, 0.58 to 1.06); however, decisions to offer kidney replacement therapy varied significantly by patient mix, acuity, and perceived benefit. There were no differences in health-related quality of life or rehospitalization among survivors.

Conclusions: Most older, critically ill patients with severe AKI were perceived as candidates for kidney replacement therapy, and approximately one half received therapy. Both willingness to offer kidney replacement therapy and reasons for not starting showed heterogeneity due to a range in patient-specific factors and clinician perceptions of benefit.